This invention relates to a barge unloading system and, more particularly, to an improvement in a system for unloading dry, bulk, particulate material from a barge, ship or other container into an intermediate holding container or pressure vessel, commonly called a reloader, and thereafter transferring the material into a storage container such as a silo.
It is well known to unload a barge by a vacuum technique where the dry, bulk, particulate material such as cement powder, grain, fertilizer or the like is transferred by suction from the barge into a pressure vessel or reloader and thereafter transferred, under pressure, into a more permanent storage container such as a silo. A system of this type is disclosed in U.S. Pat. No. 3,373,883, where a plurality of reloaders may be used and while one of the reloaders is being filled with material from the barge, the other reloader is being emptied by transferring the particulate material therefrom into a silo. This is referred to as a push-pull system because some particulate material is being pushed, by air, from one reloader to the silo while additional particulate material is being pulled, by suction, from the barge into the other reloader.
Various systems have been developed for creating a reduced pressure or suction in the reloader so that the reloader may be filled with particulate material from the barge. One such system, as described in U.S. Pat. No. 3,373,883, utilizes a source of vacuum to create the reduced pressure or suction in the reloader.
Another system, which is also well-known, is the use of a venturi to induce the desired suction necessary to fill the reloader. Specifically, as described in U.S. Pat. No. 3,372,958, air from a blower is forced through a venturi to create a primary air stream and this primary air stream induces a suction at the secondary inlet of the venturi. By connecting the secondary venturi inlet to the reloader, the induced suction draws the particulate material into the reloader from the barge.
Yet another type of venturi-induced suction system is disclosed in U.S. Pat. No. 3,861,830 which includes a cyclone type of separator for removing any dust from the suction line.
In each of the systems which operate on the venturi principle, a reciprocating valve is part of the venturi system and this valve moves between opposite positions to alternatively permit or prevent the induced suction from being created.
The present invention eliminates the need for the reciprocating valve as part of the venturi system by providing for completely by-passing the venturi during the emptying of the reloader into the pressure vessel.
The aforementioned venturi systems also include a flap-type discharge valve which operates based upon pressure differentials to alternately permit or prevent emptying of the reloader. However, the presence of any larger chunks of particulate material, such as those larger chunks which may be formed in the otherwise dry material because of some moisture or condensation during unloading has, on certain occasions, prevented the flap valve from properly and completely closing.
The present invention overcomes this problem by providing hydraulic pressure solenoid controlled valves through which the particulate material flows rather than valves which operate solely based upon pressure differentials.
Furthermore, the prior art systems, including venturi operated systems are extremely expensive to manufacture. In addition, the prior systems usually require special cranes and hoisting equipment to move the equipment relative to the barge or ship.